English

Phantom without UV pathology

High Energy Physics - Theory 2008-11-26 v2

Abstract

We present a simple model in which the weak energy condition is violated for spatially homogeneous, slowly evolving fields. The excitations about Lorentz-violating background in Minkowski space do not contain ghosts, tachyons or superluminal modes at spatial momenta ranging from some low scale epsilon to the UV cutoff scale, while tachyons and possibly ghosts do exist at p^2 < epsilon^2. We show that in the absence of other matter, slow roll cosmological regime is possible; in this regime p+rho<0, and yet homogeneity and isotropy are not completely spoiled (at the expence of fine-tuning), since for given conformal momentum, the tachyon mode grows for short enough period of time.

Keywords

Cite

@article{arxiv.hep-th/0604153,
  title  = {Phantom without UV pathology},
  author = {V. A. Rubakov},
  journal= {arXiv preprint arXiv:hep-th/0604153},
  year   = {2008}
}

Comments

19 pages. Several misprints corrected, several points clarified, several references added